Intel Broadwell-E i7-6950X & i7-6900K Review

Intelís high end desktop platform has been stagnant since Haswell-E launched in August of 2014 and while nearly 2 years may seem like an eternity for industry watchers, the new Broadwell-E processors are seeking to make up for lost time. From a company whose next moves are typically telegraphed well ahead of time, it is sometimes hard to generate any type of excitement around these launches but this time thereís certainly a few elements that will cause even the most jaded of folks to sit up and take notice. It all starts with the first 10-core, 20-thread chip available to desktop users: the positively insane i7-6950X.

Ah Broadwell-EÖ.where do I start describing what Intelís transitional microarchitecture has been through to get to this point? Due to a set of unforeseen and likely pretty darn serious mishaps its initial desktop lineup never got past an infantile state before being replaced with the Skylake platform. Haswellís erstwhile 14nm LGA1150 desktop replacement has soldiered on in relative obscurity with a pair of SKUís: the i7-5775C and i5-5675C. To this day they represent Intelís proving ground for high level Iris Pro graphics rolled into a compact and pretty efficient desktop package. Their stillborn capabilities also offer a tantalizing look into what Team Blue could accomplish if they were sincerely interested in torpedoing AMDís APU lineup.

But enough about the past, you are all here to read about Broadwell-E, a platform which began life as a server-facing product and has now made the inevitable transition to the desktop HEDT space. Indeed the Broadwell architecture does represent a step backwards from the optimizations built into current-generation Skylake processors but as with all of Intelís ultra high end initiatives, they are seeking to accomplish their goals by a very simple brute force approach.

Some will naturally wonder why Intel is even bothering with a lineup refresh for a product stack thatís priced at unattainable levels for typical users. The LGA1150 Skylake platform is efficient, comes equipped with countless features and is in general quite affordable. Think of it as the finely honed blade versus Broadwell-Eís howitzer. What these new processors do represent however is a recommitment to enthusiasts, gamers, professionals and content creators who want a no-compromise approach to performance but canít justify a stratospherically expensive Xeon-based system.

When I said expensive, I meant it. While the rest of Intelís Boradwell-E lineup closely resembles their Haswell-E predecessors in terms of feeds and speeds, the top-flight CPU this time around is a 10 core, 20 thread monster called the i7-6950X. Not only does this processor include a pretty respectable 3.5GHz Boost speed but it also packs in 25MB of shared L3 cache, support for DDR4-2400 quad channel memory and a TDP of 140W. The price for all this multi-threaded goodness is a cool $1723USD, highlighting why this end of the market needs much more competition than it currently has. That sets a new high water mark for desktop enthusiast processors, even outstripping the i7 975 Extreme Edition by a whopping 50%.

Move a bit further down-market from the 6950Xís lofty position as the thousand pound gorilla of Intelís lineup thereís the relatively pedestrian 8 core, 16 thread i7 6900K which is supposed to take over from the 5960X. It does so by retailing for the same $1089 price while offering a very small 200MHz frequency bump.

While many people will likely enjoy ogling at the performance offered by Intelís two flagships, most will likely gravitate towards the $617 i7-6850K rather than the $434 i7-6800K. When taking a look at their initial specifications only 200MHz separates these six core processors from one another. However, looking past raw processing horsepower shows us the only differentiating factor is what actually draws many enthusiasts towards this platform in the first place: PCI-E lanes. Like with Haswell-E, Intelís lowest-tier i7-6800K Broadwell-E CPU gets whittled down to just 28 Gen3 lanes, down from the 40 which grace its siblings.

Ironically, back when Ivy Bridge-E rolled out the most popular processor in its lineup was the $310 i7-4820K simply because it incorporated many of its generationís benefits without cuts to its expansion capabilities. Now weíre being told to not only pay $100 more but also stomach constrained tertiary specs. So is this heartless up selling or crafty positioning by Intel? Thatís for you to decide. On paper at least the 6800K provides a perfect bridge product between the Skylake-based 6700K and the upper echelons of Intelís current lineup. The loss of a dozen PCI-E lanes is certainly something to take into account before choosing it but with NVIDIA now focusing on double SLI over triple and quad card setups, this chip might look really, really tempting.

To be perfectly transparent, these prices have actually changed since our original briefing with Intel a few weeks ago and press werenít made specifically made aware of the update. Back then all of the information we had pointed towards the i7-6950X, i7-6900K, i7-6850K and i7-6800K retailing for $1569, $999, $587 and $412 respectively. Thatís since changed and theyíre all more expensive. Thereís some irony hidden in this somewhere but right now Iím failing to see it.

All of these processors are completely compatible with current-generation X99 motherboards provided a simple BIOS update is done. However, the motherboard vendors have been busy behind the scenes and theyíll be in the process or rolling out ďnewĒ products at launch.

The Broadwell-E architecture is a relatively straightforward thing when compared to the outgoing Haswell-E and it personifies what Intelís Tick / Tock process is all about. Whereas Haswell and Skylake are the two new processor architectures that bookend it, back when it was first launch Broadwell represented the first use of Intelís 14nm Tri-Gate transistor manufacturing process. Many figured that transition is what led to Broadwellís late launch and ultimate failure to penetrate the desktop space.

Naturally, there is a bit more to Broadwell than a simple manufacturing process shrink and corresponding frequency uplift. There are also a few minor IPC boosts brought about by more efficient pathway communication and the addition of support for Intelís new ADX instruction set. Other than the few extra cores jammed into the die courtesy of those 14nm transistors, donít expect any drastic performance uplifts versus Haswell-E.

Perhaps the most important differentiating factor between Haswell-E and these new Broadwell processors is the implementation of Intelís Turbo Boost Max 3.0. Like previous Turbo algorithms it is supposed to maximize performance by balancing thermals, power and frequency output. The best example of this is how Boost frequencies increase as the number of cores being utilized decreases. Intelís third iteration takes this to the next level by adding more granularity to the equation by adding a Windows-based software component, technically allowing Broadwell-E to hit its maximum frequencies (and above) more often. As a matter of fact, the i7-6950X and i7-6900 could hit up to 4GHz in certain single-threaded applications under the right circumstances. More about this on the next page.

Other than the addition of their top-of-the-line i7-6950X, the Broadwell-E platform seems to be a very minor step forward for Intelís enthusiast lineup. Given the competitiveness of Skylake and what seems to be a lack of any additional features to the 2011-v3 X99 motherboards for these new processors (more about this on the next page), will there be enough to alight interest in the jaded hearts of enthusiasts? Intel certainly thinks so.